I am writing some equations where I need to distinguish between bold and non-bold quantities. However, for some symbols there is barely any difference when I just use \mathbf or \boldsymbol. Is there a way to 'increase the boldness' of math symbols?

  • 2
    If you can be more specific about which symbols you find aren't bold enough, probably someone can help. A small compilable example, beginning with \documentclass and ending with \end{document} demonstrating the problem, would be even better. Jun 14 at 19:35
  • 1
    In particular, do please tell us which math font you employ.
    – Mico
    Jun 14 at 19:57
  • There is also this extensive thread on the subject: tex.stackexchange.com/q/595/118712
    – Markus G.
    Jun 14 at 19:59
  • It is hard to distinguish between bold $\alpha$ and $\beta$. I found that the problem is not that the bold is not bold enough, rather that it is bold when it is not supposed to. The problem disappears if I remove the package "mathptmx".
    – Physics101
    Jun 14 at 20:04
  • 4
    mathptmx is a very old package with very limited font support and no support for bold math symbols at all. There is no reason to use it now Jun 14 at 20:19

In comments it is stated that you are using mathptmx this is an old package targetting the fonts available in early PostScript laser printers. It has no support for bold math.




 $\alpha$ \boldmath  $\alpha$

produces the warning

Package mathptmx Warning: There are no bold math fonts on input line 7.

If you want a Times-like math font that has support for bold symbols use for example newtxmath or stix2.

enter image description here




 $\alpha$ \boldmath  $\alpha$
  • Thank you very much. I have removed the package. It was part of a template for writing articles in the Journal of Chemical Physics. It looks much better now.
    – Physics101
    Jun 15 at 7:31
  • @Physics101 OK but be careful of changing font choices on journal submissions it can invalidate the submission if it messes up the journal production. Jun 15 at 7:33
  • Thank you for the advice. The professor that I am working with will read it and help with the formalities before submission. I will ask him for a better template now.
    – Physics101
    Jun 15 at 7:39
  • @Physics101 the professor probably won't be much help; the journal might be. Most professors rely on their postdocs or even students to fiddle with that sort of detail
    – Chris H
    Jun 15 at 10:30
  • Also, with these packages, you might consider using upright greek letters \upalpha etc. in the bold cases (as \boldsymbol{\upalpha}) for extra distinction. Jun 21 at 7:03

In unicode-math, you can declare a bold math version and use \boldsymbol. XITS Math comes with one, and \setmathfont{XITS Math} will load it automatically for \boldsymbol, \boldmath and \mathversion{bold}. You could also embolden a math font with FakeBold, as in:

\setmainfont{TeX Gyre Termes}
\setmathfont{TeX Gyre Termes Math}
\setmathfont{TeX Gyre Termes Math}[
   version = bold,
   FakeBold = 1.2 ]

The one disadvantage of this is that, as of 2021, you cannot combine version= and range=.

In legacy 8-bit TeX, you normally want to load a newer font package that comes in a bold version. You can also declare a bold version for any math alphabet with e.g. \SetMathAlphabet, or a bold version of any math symbol font with \SetSymbolFont (and then optionally use the symbol font as a math alphabet as well, with \DeclareSymbolFontAlphabet). See The LaTeX Font Selection Guide for the full details.

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